I upgraded my system to a new motherboard using the NVidia nForce4 ultra chipset. Among other things, this chipset provides a gigabit ethernet port on the motherboard. Great, I can get rid of the ratty old Kingston ethernet card my DSL is plugged into. After installing NVidia's drivers, I found that I could surf the web just fine, and my own java applications could access URL's but Tomcat wouldn't respond to requests - I'm running Tomcat as my web server as well as servlet container through the Coyote connector. I know it's way past time for me to upgrade to 5.0 - I tried a quick installation of it, and it didn't seem to respond with NVidia's ethernet support either. I reverted back to my old PCI ethernet card, and Tomcat's happy again, but it might be nice to use the onboard ethernet.
Does netstat say that the addresses are properly bound ? If yes, you might want to check the firewalling features that the NF4 supposedly has, and which could be enabled by default. Anyway, this issue cannot be a Tomcat issue.